Surface Preparation
Service Overview
The quality and durability of any anodised or powder-coated finish depends heavily on the condition of the metal before finishing begins. Contaminants left from fabrication, handling, prior use, or storage, including rust, old paint, scuff marks, oils, and surface material, can impair adhesion, cause inconsistencies in colour and finish, and reduce the long-term durability of the coating. Correct preparation removes these risks before they become finishing failures.
Astro Group offers three in-house preparation methods for small aluminium and steel components: bead blasting, soda or vapour blasting, and tumbling. All three are available prior to anodising or powder coating.
Please note: preparation methods are currently available for small components only.
Sandblasting (Bead Blasting)
Available for aluminium and steel
Most components arrive with some level of surface contamination. It may be scuff marks from handling, rust from storage, old paint from a previous finish, or material left from fabrication. Bead blasting removes all of it.
The process forces fine bead particles at high velocity against the surface using compressed air, smoothing and cleaning the metal uniformly across the whole component. The result is a clean, consistent surface ready for anodising or powder coating, without localised marks or contamination showing through the finished coat.
Bead blasting is one of the most versatile preparation methods available, suitable for both aluminium and steel across a wide range of component types and surface conditions.
Soda or Vapour Blasting
Available for aluminium only. Maximum component size: 800mm x 800mm x 800mm.
Not every component can withstand an abrasive process. Soda blasting uses compressed air to propel aerosolised sodium bicarbonate mixed with water against the component surface. Unlike bead blasting, it does not abrade the surface, making it gentler on the base material and better suited to components where surface integrity must be maintained. It is particularly effective at removing light rust, old paint, and surface oxidation. Vapour blasting works on a similar principle and can also be used to improve the overall surface quality of the material before finishing.
Please note: soda or vapour blasting is available for aluminium only. Component sizes cannot exceed 800mm x 800mm x 800mm.
Tumbling
Available for aluminium and steel, in small quantities and sizes.
Some components are too small, or too complex in geometry, to blast individually. Tumbling handles these efficiently.
Small components are placed in a circular vibrating drum filled with abrasive beads. As the drum vibrates, the beads work against all exposed surfaces simultaneously, removing unwanted material, and polishing the component to a smooth, consistent finish.
Which Method is Right for Your Components?
The right preparation method depends on the material, the size of the component, its current surface condition, and the finishing process being applied.
If you are unsure which preparation method is most appropriate for your components, please enquire directly. Our team will advise based on the material, size, current surface condition, and finishing requirements of your parts.
Why Surface Preparation Matters
A finishing failure rarely starts at the finishing stage. It starts earlier, with a surface that was not properly prepared before coating was applied. Poor adhesion, colour inconsistency, premature corrosion, and finishes that fail to meet specification are almost always the result of inadequate preparation rather than a problem with the finishing process itself.
For anodised finishes, the surface condition before processing directly affects the uniformity of the oxide layer and the consistency of colour absorption. Components that have been welded, machined, or handled before anodising are particularly susceptible to contamination that will show in the finished product.
For powder-coated finishes, the powder must bond to a clean, correctly prepared surface. Contamination prevents proper adhesion and reduces the durability of the coating over time, particularly in external or high-exposure environments.
Getting the preparation right is the most effective way to protect the quality of the finished component.
Aluminium 360° | Our Turnkey Approach
Surface preparation is one part of our Aluminium 360° offering. If your project requires aluminium sourcing and supply, fabrication, or surface finishing alongside this service, all are available in-house.
Frequently Asked Questions
Which preparation method should I use before anodising?
The most appropriate method depends on the material, size, and current surface condition of the component. Bead blasting is the most versatile option for aluminium and steel. Soda blasting is recommended for aluminium components requiring a gentler approach. Tumbling is recommended for small batch components requiring polishing and deburring. If you are unsure, please enquire directly and our team will advise.
Which preparation method should I use before powder coating?
Bead blasting and tumbling are both suitable before powder coating. Soda blasting is not typically used before powder coating. Correct preparation is essential to achieving a durable, well-bonded powder-coated finish.
Get In Touch
Ready to discuss your requirements?
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